Lettuce variety 41-122 RZ

ABSTRACT

The present invention relates to a  Lactuca sativa  seed designated 41-122 RZ, which may exhibit resistance to downy mildew ( Bremia lactucae  Regel.), and which may have leaves with a solid main vein, narrow base leaves, and thick, strongly blistered, dark green mature leaves. The present invention also relates to a  Lactuca sativa  plant produced by growing the 41-122 RZ seed. The invention further relates to methods for producing the lettuce cultivar, represented by lettuce variety 41-122 RZ.

RELATED APPLICATIONS AND INCORPORATION BY REFERENCE

This application which claims priority to U.S. provisional patentapplication Ser. No. 61/492,929 filed 3 Jun. 2011.

The foregoing application, and all documents cited therein or duringtheir prosecution (“appln cited documents”) and all documents cited orreferenced in the appln cited documents, and all documents cited orreferenced herein (“herein cited documents”), and all documents cited orreferenced in herein cited documents, together with any manufacturer'sinstructions, descriptions, product specifications, and product sheetsfor any products mentioned herein or in any document incorporated byreference herein, are hereby incorporated herein by reference, and maybe employed in the practice of the invention. More specifically, allreferenced documents are incorporated by reference to the same extent asif each individual document was specifically and individually indicatedto be incorporated by reference.

FIELD OF THE INVENTION

The present invention relates to a new lettuce (Lactuca sativa) varietywhich may be suitable for mechanical harvest and exhibits resistanceagainst downy mildew (Bremia lactucae) as well as thick, stronglyblistered leaves.

BACKGROUND OF THE INVENTION

Romaine lettuce should provide a product at harvestable stage, which isaccepted by processing industry and/or consumers. Therefore theharvestable product should not have tipburn, should have a short core,and it should have thick, strongly blistered leaves with a dark greenouter leaf color. Further it should be sufficiently headed, and as aresult of this heading provide sufficient yellow-colored heartleaves.

Mature romaine lettuce is mainly harvested by hand. This harvestingprocess is labor-intensive, and relatively laborer-unfriendly. As itgetting more and more costly to hire laborers that want to work outdoorin the field, close to the ground and under all kinds of adverse weatherconditions, there is strong interest of the lettuce industry tomechanize this manual harvesting process. However, until now the lack ofuniform quality among mature plants is a major problem for mechanicalharvest. Poor quality of basal leaves, internal breakdown of heartleavesdue to tipburn, fringe burn of leaf margins and fast bolting are themain quality problems. If one would like to mechanize the harvestprocess, these quality problems result in additional hand sorting, whichis costly, and/or a very low net yield, if the plant parts with a highrisk of quality problems are mechanically discarded. The latter approachis chosen by some producers that produce romaine hearts, i.e. the intactyellow-green heart of the romaine lettuce without the green outerleaves. For producers that produce romaine lettuce for processing, i.e.pre-washed and pre-cut leaves, this is not feasible because of fourmajor constraints.

The first is the requirement for a mix of green and yellow leaves, whichrequires the preservation of the undamaged green outer leaves. Thesecond constraint is the strongly reduced net yield, which is a resultof the fact that an automated knife should cut through the leaf but notthrough the core. Especially fast bolting lettuce varieties areunacceptable for mechanized harvest of romaine lettuce for processingpurposes because of their long core.

The third constraint is caused by the use of mechanically-drivenhorizontal knives that easily damage the hollow main veins of romaineleaves and cut halfway through the prostrate, round-shaped, lower outerleaves, which results in wide cut surfaces. Cutting damage on a leafwith a hollow main vein is often not restricted to the cut surface butbruising extends into the leaf along the main vein.

The fourth constraint is the requirement for a leaf to have a good shelflife. This means the leaves should get through the washing and dryingprocess in the factory without bruising or breaking. The leaves shouldbe sufficiently thick and tough to avoid wilting. In addition, theleaves should be strongly blistered to avoid sticking to each other andto the plastic of the packaging, which increases local humidity on theleaf and reduces local respiration.

There exists a need, therefore, for a new type of romaine or coslettuce, which is suitable for mechanical harvest with a simplehorizontal knife and which exhibits resistance against downy mildew(Bremia lactucae). The harvested product is meant for processingpurposes.

Citation or identification of any document in this application is not anadmission that such document is available as prior art to the presentinvention.

SUMMARY OF THE INVENTION

It is the object of the invention to provide a new type of romaine orcos lettuce, which may be suitable for mechanical harvest with a simplehorizontal knife, and which does not have or has reduced problems withdowny mildew. The harvested product may be for processing purposes.

The present invention fulfils this need by providing a new romaine, orcos, lettuce (Lactuca sativa L. var. longifolia Lam) variety, designated41-122 RZ. Lettuce variety 41-122 RZ which may exhibit a combination oftraits including leaves with a solid main vein, narrow base leaves andBremia-resistance, as well as thick, strongly blistered, dark greenouter leaves, a short core, absence of fringe burn, and absence oftipburn.

The present invention provides seeds of lettuce cultivar 41-122 RZ,which have been deposited with the National Collections of Industrial,Marine and Food Bacteria (NCIMB) in Bucksburn, Aberdeen AB21 9YA,Scotland, UK and have been assigned NCIMB Accession No. 41832.

In one embodiment, the invention provides a lettuce plant exhibiting acombination of traits including resistance against downy mildew (Bremialactucae), leaves with a solid main vein, narrow base leaves, and thick,strongly blistered, mature leaves, representative seed of which havebeen deposited under NCIMB Accession No. 41832.

In one embodiment, the invention provides a lettuce plant exhibiting acombination of traits including resistance against downy mildew (Bremialactucae), leaves with a solid main vein, narrow base leaves, thick,strongly blistered, mature leaves, a short core, absence of fringe burn,absence of tipburn, no undulation of the fourth leaf, and very slowbolting, representative seed of which have been deposited under NCIMBAccession No. 41832.

In one embodiment, the invention provides a lettuce plant designated41-122 RZ, representative seed of which have been deposited under NCIMBAccession No. 41832.

In an embodiment of the present invention, there also is provided partsof a lettuce plant of the invention, including parts of a lettuce plantexhibiting a combination of traits including resistance against downymildew (Bremia lactucae), leaves with a solid main vein, narrow baseleaves, and thick, strongly blistered, mature leaves, or parts of alettuce plant having any of the aforementioned resistance(s) and acombination of traits including one or more morphological orphysiological characteristics tabulated herein, including parts oflettuce variety 41-122 RZ, wherein the plant parts are involved insexual reproduction, which include, without limitation, microspores,pollen, ovaries, ovules, embryo sacs or egg cells and/or wherein theplant parts are suitable for vegetative reproduction, which include,without limitation, cuttings, roots, stems, cells or protoplasts and/orwherein the plant parts are tissue culture of regenerable cells in whichthe cells or protoplasts of the tissue culture are derived from a tissuesuch as, for example and without limitation, leaves, pollen, embryos,cotyledon, hypocotyls, meristematic cells, roots, root tips, anthers,flowers, seeds or stems. The plants of the invention from which suchparts may come from include those wherein representative seed of whichhas been deposited under NCIMB Accession No. 41832.

In another embodiment there may be a plant grown from seeds,representative seed of which having been deposited under NCIMB AccessionNo. 41832. In a further embodiment there may be a plant regenerated fromthe above-described plant parts or regenerated from the above-describedtissue culture. Advantageously such a plant may have morphologicaland/or physiological characteristics of lettuce variety 41-122 RZ and/orof a plant grown from seed, representative seed of which having beendeposited under NCIMB Accession No. NCIMB 41832—including withoutlimitation such plants having all of the morphological and physiologicalcharacteristics of lettuce variety 41-122 RZ and/or of plant grown fromseed, representative seed of which having been deposited under NCIMBAccession No. NCIMB 41832. Accordingly, in still a further embodiment,there is provided a lettuce plant having all of the morphological andphysiological characteristics of lettuce variety 41-122 RZ,representative seed of which having been deposited under NCIMB AccessionNo. 41832. Such a plant may be grown from the seeds, regenerated fromthe above-described plant parts, or regenerated from the above-describedtissue culture. A lettuce plant having any of the aforementionedresistance(s), a lettuce plant having any of the aforementionedresistance(s) and one or more morphological or physiologicalcharacteristics recited or tabulated herein, and a lettuce plantadvantageously having all of the aforementioned resistances and thecharacteristics recited and tabulated herein, are preferred. Parts ofsuch plants—such as those plant parts above-mentioned—are encompassed bythe invention.

In one embodiment, there is provided progeny of lettuce cultivar 41-122RZ produced by sexual or vegetative reproduction, grown from seeds,regenerated from the above-described plant parts, or regenerated fromthe above-described tissue culture of the lettuce cultivar or a progenyplant thereof, representative seed of which having been deposited underNCIMB Accession No. 41832.

Progeny of the lettuce variety 41-122 RZ may be modified in one or moreother characteristics, in which the modification is a result of, forexample and without limitation, mutagenesis or transformation with atransgene.

In still another embodiment, the present invention provides progeny oflettuce cultivar 41-122 RZ produced by sexual or vegetativereproduction, grown from seeds, regenerated from the above-describedplant parts, or regenerated from the above-described tissue culture ofthe lettuce cultivar or a progeny plant thereof, in which theregenerated plant shows a combination of traits including resistanceagainst downy mildew (Bremia lactucae), leaves with a solid main vein,narrow base leaves, and thick, strongly blistered, mature leaves.

In still a further embodiment, the invention may comprise a method ofproducing a hybrid lettuce seed comprising crossing a first parentlettuce plant with a second parent lettuce plant and harvesting theresultant hybrid lettuce seed, in which the first parent lettuce plantor the second parent lettuce plant is a lettuce plant of the invention,e.g. a lettuce plant having a combination of traits including resistanceagainst downy mildew (Bremia lactucae), leaves with a solid main vein,narrow base leaves, and thick, strongly blistered, mature leaves and oneor more morphological or physiological characteristics tabulated herein,including a lettuce plant of lettuce cultivar 41-122 RZ, representativeseed of which having been deposited under NCIMB 41832.

In another embodiment, the invention may comprise producing a lettuceplant having a combination of traits including resistance against downymildew (Bremia lactucae), leaves with a solid main vein, narrow baseleaves, and thick, strongly blistered, mature leaves comprising:crossing a mother lettuce plant with a father lettuce plant to produce ahybrid seed; growing said hybrid seed to produce a hybrid plant; selfingsaid hybrid seed to produce F2 progeny seed; selecting said F2-plantsfor exhibiting a combination of traits including resistance againstdowny mildew (Bremia lactucae), leaves with a solid main vein, narrowbase leaves, and thick, strongly blistered, mature leaves.

Advantageously the selfing and selection may be repeated; for example atleast once, or at least twice, thrice, four times, five times, six timesor more, to produce F3 or F4 or F5 or F6 or subsequent progeny,especially as progeny from F2 can exhibit the aforementioned combinationof traits, and can be desirable.

In still a further embodiment, the invention may comprise a method ofproducing a lettuce cultivar containing a combination of traitsincluding resistance against downy mildew (Bremia lactucae), leaves witha solid main vein, narrow base leaves, and thick, strongly blistered,mature leaves.

The invention even further relates to a method of producing lettucecomprising: (a) cultivating to the vegetative plant stage a plant oflettuce variety 41-122 RZ, representative seed of which having beendeposited under NCIMB Accession No. NCIMB 41832, and (b) harvestinglettuce leaves or heads from the plant. The invention furthercomprehends packaging the lettuce plants, heads or leaves.

Accordingly, it is an object of the invention to not encompass withinthe invention any previously known product, process of making theproduct, or method of using the product such that Applicants reserve theright and hereby disclose a disclaimer of any previously known product,process, or method. It is further noted that the invention does notintend to encompass within the scope of the invention any product,process, or making of the product or method of using the product, whichdoes not meet the written description and enablement requirements of theUSPTO (35 U.S.C. §112, first paragraph) or the EPO (Article 83 of theEPC), such that Applicants reserve the right and hereby disclose adisclaimer of any previously described product, process of making theproduct, or method of using the product.

It is noted that in this disclosure and particularly in the claims,terms such as “comprises”, “comprised”, and “comprising” and the like(e.g., “includes”, “included”, “including”, “contains”, “contained”,“containing”, “has”, “had”, “having”, etc.) can have the meaningascribed to them in US Patent law, i.e., they are open ended terms. Forexample, any method that “comprises,” “has” or “includes” one or moresteps is not limited to possessing only those one or more steps and alsocovers other unlisted steps. Similarly, any plant that “comprises,”“has” or “includes” one or more traits is not limited to possessing onlythose one or more traits and covers other unlisted traits. Similarly,the terms “consists essentially of” and “consisting essentially of” havethe meaning ascribed to them in US Patent law, e.g., they allow forelements not explicitly recited, but exclude elements that are found inthe prior art or that affect a basic or novel characteristic of theinvention. See also MPEP §2111.03. In addition, the term “about” is usedto indicate that a value includes the standard deviation of error forthe device or method being employed to determine the value.

These and other embodiments are disclosed or are obvious from andencompassed by the following Detailed Description.

DEPOSIT

The Deposit with NCIMB Ltd, Ferguson Building, Craibstone Estate,Bucksburn, Aberdeen AB21 9YA, UK, on May 4, 2011, under depositaccession number NCIMB 41832 was made pursuant to the terms of theBudapest Treaty. Upon issuance of a patent, all restrictions upon thedeposit will be removed, and the deposit is intended to meet therequirements of 37 CFR §1.801-1.809. The deposit will be maintained inthe depository for a period of 30 years, or 5 years after the lastrequest, or for the effective life of the patent, whichever is longer,and will be replaced if necessary during that period.

BRIEF DESCRIPTION OF THE DRAWINGS

The following detailed description, given by way of example, but notintended to limit the invention solely to the specific embodimentsdescribed, may best be understood in conjunction with the accompanyingdrawings, in which:

FIG. 1 shows a transverse section at 40% of leaf lamina length toobserve solidness of main vein.

FIG. 2 is an illustration of six different shapes of the fourth leaffrom a 20-day old seedling grown under optimal conditions.

FIG. 3 shows a mature leaf of 41-122 RZ (right), as compared to varietyActarus (left) and variety Easala (middle).

DETAILED DESCRIPTION OF THE INVENTION

The invention provides methods and compositions relating to plants,seeds and derivatives of a new lettuce variety herein referred to aslettuce variety 41-122 RZ. Lettuce variety 41-122 RZ is a uniform andstable line, distinct from other such lines.

In a preferred embodiment, the specific type of breeding method employedfor developing a lettuce cultivar is pedigree selection, where bothsingle plant selection and mass selection practices are employed.Pedigree selection, also known as the “Vilmorin system of selection,” isdescribed in Fehr, W., Principles of Cultivar Development, Volume I,MacMillan Publishing Co., which is hereby incorporated by reference.

When pedigree selection is applied, in general selection is firstpracticed among F₂ plants. In the next season, the most desirable F₃lines are first identified, and then desirable F₃ plants within eachline are selected. The following season and in all subsequentgenerations of inbreeding, the most desirable families are identifiedfirst, then desirable lines within the selected families are chosen, andfinally desirable plants within selected lines are harvestedindividually. A family refers to lines that were derived from plantsselected from the same progeny from the preceding generation.

Using this pedigree method, two parents may be crossed using anemasculated female and a pollen donor (male) to produce F₁ offspring.Lettuce is an obligate self-pollination species, which means that pollenis shed before stigma emergence, assuring 100% self-fertilization.Therefore, in order to optimize crossing, a method of misting may beused to wash the pollen off prior to fertilization to assure crossing orhybridization.

Parental varieties are selected from commercial varieties thatindividually exhibit one or more desired phenotypes. Additionally, anybreeding method involving selection of plants for the desired phenotypecan be used in the method of the present invention.

The F₁ may be self-pollinated to produce a segregating F₂ generation.Individual plants may then be selected which represent the desiredphenotype in each generation (F₃, F₄, F₅, etc.) until the traits arehomozygous or fixed within a breeding population.

Lettuce variety 41-122 RZ was developed by crossing two varieties,‘Hearts Delight’ and ‘Actarus’, in a glasshouse in Aramon, France, in2004. The F1 resulting from this cross was grown under protectedconditions. A population of F2 seed was obtained throughself-pollination. When growing the F2 population in 2005, selection formultiple characteristics was performed, and specifically forBremia-resistance, a solid main vein, and thick, strongly blisteredleaves. One F2 plant, 05A.22621 was selected in Aramon, and this plantwas self-pollinated to obtain F3 seed, designated 06A.52088.

The F3 seed was sown in Fijnaart, The Netherlands, in 2006, and after asubsequent round of selection for multiple characteristics includingBremia-resistance, a solid main vein, and thick, strongly blisteredleaves, an F3 plant was selected, namely 06A.71757. The plant was selfpollinated and F4 seed, 07A.51705, was produced. Subsequently, the F4was sown in the field in Tarascon, France, in 2007 as 07A.26116, and anF4 plant was selected from the population after selection for preferredcharacteristics including Bremia resistance, a solid main vein, andthick, strongly blistered leaves. Self pollination was performed, and F5seed 08A.51674 was produced.

In 2008 (France) and 2009 (The Netherlands) two more rounds of selectionto optimize the uniformity of the line were done, resulting in F6 seed09A.41714 and, after selecting and selfing the F6 plant 09A.71747, an F7seedlot 10A.40907.

The seed from the F7 line 10R.990238 was established to be uniform, andmultiplied in the glasshouse in Fijnaart in 2010, to obtain F8 seed lot10R.238. 2500 seeds from this seed lot were deposited under AccessionNo. NCIMB 41832 on May 4, 2011.

In one embodiment, a plant of the invention has all the morphologicaland physiological characteristics of lettuce variety 41-122 RZ. Thesecharacteristics of a lettuce plant of the invention, e.g. variety 41-122RZ, are summarized in Tables 1-4.

Next to the morphological and physiological characteristics mentioned inTables 1-4, a plant of the invention also exhibits resistance to downymildew (Bremia lactucae Regel.).

As used herein, resistance against Bremia lactucae Regel is defined asthe ability of a plant to resist infection by various strains of Bremialactucae Regel. in all stages between the seedling stage and theharvestable plant stage via a hypersensitivity response (Crute, I. R.,Annual Rev. Phytopathol., 30:485-506, 1992; incorporated herein byreference). The various strains against which 41-122 RZ exhibitsresistance are NL1, NL2, NL4, NL5, NL6, NL7, NL10, NL12, NL13, NL14,NL15, Bl:17, Bl:18, Bl:20, Bl:21, Bl:22, Bl:24, Bl:25, and Bl:26, (VanEttekoven K, Van der Arend A J M, 1999. In: Lebeda A, Kristkova E (eds.)Eucarpia leafy vegetables '99. Palacky University, Olomouc, CzechRepublic, 1999: 171-175; Van der Arend et al., 2003. In: Van Hintum etal. (Eds.) Eucarpia Leafy Vegetables 2003. CGN, Wageningen, theNetherlands 2003: 151; Van der Arend et al., 2006. In: Pink et al.(Eds.) Eucarpia Leafy Vegetables 2006. Warwick HRI, Wellesbourne, UK,2007 incorporated herein by reference), Ca-V, Ca-VI, Ca-VII, Ca-VIII(Michelmore R. & Ochoa. O. “Breeding Crisphead Lettuce.” In: CaliforniaLettuce Research Board, Annual Report 2005-2006, 2006, Salinas, Calif.,pp. 55-68).

Resistance typically is tested by two interchangeable methods, describedby Bonnier, F. J. M. et al. (Euphytica, 61(3):203-211, 1992;incorporated herein by reference). One method involves inoculating 7-dayold seedlings, and observing sporulation 10 to 14 days later. The othermethod involves inoculating leaf discs with a diameter of 18 mm obtainedfrom a non-senescent, fully grown true leaf and observing sporulation 10days later.

As used herein, romaine is Lactuca sativa L. var. longifolia Lam; alsoknown as cos. The plant develops in an upright open or upright compactgrowing habit with coarse textured leafs. The younger leaves are longerthan they are wide, fifteen cupping together to form an elongated loosehead. Leaf margins are often entire or undulated, rarely frilled. Outerleaves range in color from light green to dark green. Inner heartleavesare smaller and range from light yellow to light green in color.

As used herein, a solid main vein is the main vein of a fully-growntenth to fifteenth leaf, which is characterized by the fact that thevein is not hollow, which is observed by visual inspection of atransverse section of the leaf. The transverse section should be made at40% of the total leaf length, starting from the leaf base (see FIG. 1).For comparison two standard varieties can be used: Maximus, with hollowveins, and Tiberius, with solid veins.

As used herein, a narrow base leaf is characterized by alength/width-ratio of 1.5 or higher. A mature romaine lettuce plant hasgot narrow base leaves if the average length/width-ratio of thefully-grown tenth to the fifteenth leaf is 1.5 or higher. For comparisontwo standard varieties can be used: Maximus with broad base leaves, andChilim with narrow base leaves.

As used herein, dark green outer leaves or dark green mature leaves aredefined by the color of a fully-grown tenth to fifteenth leaf, whichshould be similar to or darker than 137B, 138A, 144A, or 146A on the RHScolor chart (The Royal Horticultural Society, London, UK).

As used herein, thick leaves are characterized by a thick, slightlytough leaf texture. For comparison the standard variety “Parris Island”can be used. As used herein, intermediate thick leaves are characterisedby a flexible leaf texture, which is less thick than “Parris Island”.For comparison the standard variety “Blonde Lente à Monter” can be used.

As used herein, strongly blistered leaves are characterised by a highdensity of leaf bubbles. For comparison the standard variety “PrizeHead” can be used. As used herein moderately blistered leaves arecharacterised by a intermediate density of leaf bubbles. For comparisonthe standard variety “Vanguard” can be used.

As used herein, a short core is defined by measuring the length of thecore of a harvested mature plant with outer leaves attached. The plantshould be grown outdoor under long-day conditions: sowing 5-15 daysbefore the longest day in a mild mid-latitude climate with a warm summer(Köppen-classification: Csb or Cfb; McKnight & Hess, 2000. PhysicalGeography: A Landscape Appreciation. Upper Saddle River, N.J.: PrenticeHall). A mature plant grown under these conditions is defined as beingheaded and having a weight of 600-1000 g after harvest. The core of sucha plant is defined as ‘short’ if its length is less than or equal to 8cm.

As used herein, absence of fringe burn is established by growing plantsin outdoor conditions in a winter production area for lettuce with anaverage daily temperature of the coldest month between 11 and 14 C, forexample Cartagena, Spain or Yuma, USA. The growing cycle under theseconditions should be at least 16 weeks from sowing a seed to harvestinga mature plant. Harvesting the mature plant should take place in themonth after the coldest month. Absence of fringe burn is defined byobserving the leaf margin of the tenth until the fifteenth leaf. Absenceof fringe burn is established, if for each of these leaves less than 2%of the perimeter of the leaf margin is necrotic.

As used herein, absence of tipburn is established by growing plants inoutdoor conditions in spring conditions in a winter production area forlettuce with an average daily temperature of the coldest month between11 and 14 C, for example Cartagena, Spain or Yuma, USA. Harvesting themature plant should take place in the third month after the coldestmonth. Absence of tipburn is defined by observing the ten most recentlydeveloped heart leaves longer than 5 cm. Absence of tipburn isestablished, if for each of these leaves less than 1% of the perimeterof the leaf margin is necrotic. The additional requirement forestablishing absence of tipburn is that the comparison variety Maximus,grown under the same conditions with the same sowing and harvest date,shows presence of tipburn, and a second comparison variety Optimus,grown under the same conditions with the same sowing and harvest date,shows absence of tipburn. Presence of tipburn is established, if for atleast one out of the ten most recently developed heart leaves longerthan 5 cm, at least 1% of the perimeter of the leaf margin is necrotic.

Embodiments of the inventions advantageously have one or more, and mostadvantageously all, of these characteristics.

In Table 1 that follows, the traits and characteristics of the Lactucasativa L. var. longifolia Lam romaine lettuce plant having thedesignation 41-122 RZ, are given compared to the mentioned comparisonvarieties, referred to as “Tiberius”, “Maximus”, “Optimus”, and“Chilim”.

TABLE 1 Character “41-122 RZ” “Tiberius” “Maximus” “Optimus” “Chilim”Type romaine or cos romaine or cos romaine or cos romaine or romaine orcos cos hollow/solid main solid solid hollow hollow hollow veinbroad/narrow base narrow broad broad broad narrow leaves blond/darkgreen dark dark dark blond blond color core length short long shortshort long tipburn absent present present absent present fringe burnabsent absent absent present present

In the Tables that follow, the traits and characteristics of the Lactucasativa L. var. longifolia Lam romaine lettuce plant referred to as“41-122 RZ” are given, compared to the most similar variety, referred toas “Actarus” and a standard regional check variety, referred to as“Parris Island.”

In Table 2, the seed color, cotyledon shape and characteristics of thefourth leaf of “41-122 RZ” is compared with “Actarus” and “ParrisIsland.” RHS=Royal Horticultural Society colour chart code.

TABLE 2 Character “41-122 RZ” “Actarus” “Parris Island” Plant TypeRomaine or Cos Romaine or Cos Romaine or Cos Seed Color White (SilverGray) White (Silver Gray) White (Silver Gray) Cotyledon Shape Broadbroad Intermediate Shape of Fourth Leaf No. 4 on FIG. 2 No. 4 on FIG. 2No. 4 on FIG. 2 Rolling of Fourth Leaf Absent Absent Absent Cupping ofFourth Leaf Uncupped Uncupped Uncupped Fourth Leaf Apical Entire EntireEntire Margin Undulation Flat Flat Flat

In Table 3, the mature leaf and head characteristics of “41-122 RZ” iscompared with “Actarus” and “Parris Island.”

TABLE 3 Character “41-122 RZ” “Actarus” “Parris Island” Green Color RHS137B RHS 137B RHS 137A Anthocyanin Absent Absent Absent DistributionMargin Incision Depth Absent/Shallow Absent/Shallow Absent/ShallowMargin Indentation Shallowly Dentate Shallowly Dentate Shallowly DentateUndulations of the Absent/Slight Absent/Slight Absent/Slight ApicalMargin Leaf Size Large to Medium Large to Medium Large Leaf GlossinessModerate Moderate Moderate to Dull Leaf Blistering Strong ModerateModerate Leaf Thickness Thick Intermediate Intermediate to ThickTrichomes Absent (Smooth) Absent (Smooth) Absent (smooth) Head ShapeElongate Elongate Elongate Head Size Medium Medium Large Head FirmnessModerate Moderate Firm Butt Shape Rounded Rounded Rounded MidribProminently Raised Prominently Raised Prominently Raised

In Table 4, the characteristics of the core and the bolter plant of“41-122 RZ” is compared with “Actarus” and “Parris Island.”

TABLE 4 Character “41-122 RZ” “Actarus” “Parris Island” Bolting ClassVery Slow Very Slow Slow Bolter Leaves Straight Straight Slightly CurvedMargin Slightly Dentate Dentate Slightly Dentate Color RHS 137A RHS 137ARHS 137B Terminal Inflorescence Present Present Present Lateral ShootsPresent Present Present Basal Side Shoots Present Present Present

In an embodiment, the invention relates to lettuce plants that has allthe morphological and physiological characteristics of the invention andhave acquired said characteristics by introduction of the geneticinformation that is responsible for the characteristics from a suitablesource, either by conventional breeding, or genetic modification, inparticular by cisgenesis or transgenesis. Cisgenesis is geneticmodification of plants with a natural gene, coding for an (agricultural)trait, from the crop plant itself or from a sexually compatible donorplant. Transgenesis is genetic modification of a plant with a gene froma non-crossable species or a synthetic gene.

Just as useful traits that can be introduced by backcrossing, usefultraits can be introduced directly into the plant of the invention, beinga plant of lettuce variety 41-122 RZ, by genetic transformationtechniques; and, such plants of lettuce variety 41-122 RZ that haveadditional genetic information introduced into the genome or thatexpress additional traits by having the DNA coding there for introducedinto the genome via transformation techniques, are within the ambit ofthe invention, as well as uses of such plants, and the making of suchplants.

Genetic transformation may therefore be used to insert a selectedtransgene into the plant of the invention, being a plant of lettucevariety 41-122 RZ or may, alternatively, be used for the preparation oftransgenes which can be introduced by backcrossing. Methods for thetransformation of plants, including lettuce, are well known to those ofskill in the art.

Vectors used for the transformation of lettuce cells are not limited solong as the vector can express an inserted DNA in the cells. Forexample, vectors comprising promoters for constitutive gene expressionin lettuce cells (e.g., cauliflower mosaic virus 35S promoter) andpromoters inducible by exogenous stimuli can be used. Examples ofsuitable vectors include pBI binary vector. The “lettuce cell” intowhich the vector is to be introduced includes various forms of lettucecells, such as cultured cell suspensions, protoplasts, leaf sections,and callus. A vector can be introduced into lettuce cells by knownmethods, such as the polyethylene glycol method, polycation method,electroporation, Agrobacterium-mediated transfer, particle bombardmentand direct DNA uptake by protoplasts. To effect transformation byelectroporation, one may employ either friable tissues, such as asuspension culture of cells or embryogenic callus or alternatively onemay transform immature embryos or other organized tissue directly. Inthis technique, one would partially degrade the cell walls of the chosencells by exposing them to pectin-degrading enzymes (pectolyases) ormechanically wound tissues in a controlled manner.

A particularly efficient method for delivering transforming DNA segmentsto plant cells is microprojectile bombardment. In this method, particlesare coated with nucleic acids and delivered into cells by a propellingforce. Exemplary particles include those comprised of tungsten,platinum, and preferably, gold. For the bombardment, cells in suspensionare concentrated on filters or solid culture medium. Alternatively,immature embryos or other target cells may be arranged on solid culturemedium. The cells to be bombarded are positioned at an appropriatedistance below the macroprojectile stopping plate. An illustrativeembodiment of a method for delivering DNA into plant cells byacceleration is the Biolistics Particle Delivery System, which can beused to propel particles coated with DNA or cells through a screen, suchas a stainless steel or Nytex screen, onto a surface covered with targetlettuce cells. The screen disperses the particles so that they are notdelivered to the recipient cells in large aggregates. It is believedthat a screen intervening between the projectile apparatus and the cellsto be bombarded reduces the size of projectiles aggregate and maycontribute to a higher frequency of transformation by reducing thedamage inflicted on the recipient cells by projectiles that are toolarge. Microprojectile bombardment techniques are widely applicable, andmay be used to transform virtually any plant species, including a plantof lettuce variety 41-122 RZ.

Agrobacterium-mediated transfer is another widely applicable system forintroducing gene loci into plant cells. An advantage of the technique isthat DNA can be introduced into whole plant tissues, thereby bypassingthe need for regeneration of an intact plant from a protoplast.Agrobacterium transformation vectors are capable of replication in E.coli as well as Agrobacterium, allowing for convenient manipulations.Moreover, advances in vectors for Agrobacterium-mediated gene transferhave improved the arrangement of genes and restriction sites in thevectors to facilitate the construction of vectors capable of expressingvarious polypeptide coding genes. The vectors have convenientmulti-linker regions flanked by a promoter and a polyadenylation sitefor direct expression of inserted polypeptide coding genes.Additionally, Agrobacterium containing both armed and disarmed Ti genescan be used for transformation. In those plant strains whereAgrobacterium-mediated transformation is efficient, it is the method ofchoice because of the facile and defined nature of the gene locustransfer. The use of Agrobacterium-mediated plant integrating vectors tointroduce DNA into plant cells, including lettuce plant cells, is wellknown in the art (See, e.g., U.S. Pat. Nos. 7,250,560 and 5,563,055).

Transformation of plant protoplasts also can be achieved using methodsbased on calcium phosphate precipitation, polyethylene glycol treatment,electroporation, and combinations of these treatments.

A number of promoters have utility for plant gene expression for anygene of interest including but not limited to selectable markers,scoreable markers, genes for pest tolerance, disease resistance,nutritional enhancements and any other gene of agronomic interest.Examples of constitutive promoters useful for lettuce plant geneexpression include, but are not limited to, the cauliflower mosaic virus(CaMV) P-35S promoter, a tandemly duplicated version of the CaMV 35Spromoter, the enhanced 35S promoter (P-e35S), the nopaline synthasepromoter, the octopine synthase promoter, the figwort mosaic virus(P-FMV) promoter (see U.S. Pat. No. 5,378,619), an enhanced version ofthe FMV promoter (P-eFMV) where the promoter sequence of P-FMV isduplicated in tandem, the cauliflower mosaic virus 19S promoter, asugarcane bacilliform virus promoter, a commelina yellow mottle viruspromoter, the promoter for the thylakoid membrane proteins from lettuce(psaD, psaF, psaE, PC, FNR, atpC, atpD, cab, rbcS) (see U.S. Pat. No.7,161,061), the CAB-1 promoter from lettuce (see U.S. Pat. No.7,663,027), the promoter from maize prolamin seed storage protein (seeU.S. Pat. No. 7,119,255), and other plant DNA virus promoters known toexpress in plant cells. A variety of plant gene promoters that areregulated in response to environmental, hormonal, chemical, and/ordevelopmental signals can be used for expression of an operably linkedgene in plant cells, including promoters regulated by (1) heat, (2)light (e.g., pea rbcS-3A promoter, maize rbcS promoter, or chlorophylla/b-binding protein promoter), (3) hormones, such as abscisic acid, (4)wounding (e.g., wunl, or (5) chemicals such as methyl jasmonate,salicylic acid, or Safener. It may also be advantageous to employorgan-specific promoters.

Exemplary nucleic acids which may be introduced to the lettuce varietyof this invention include, for example, DNA sequences or genes fromanother species, or even genes or sequences which originate with or arepresent in lettuce species, but are incorporated into recipient cells bygenetic engineering methods rather than classical reproduction orbreeding techniques. However, the term “exogenous” is also intended torefer to genes that are not normally present in the cell beingtransformed, or perhaps simply not present in the form, structure, etc.,as found in the transforming DNA segment or gene, or genes which arenormally present and that one desires to express in a manner thatdiffers from the natural expression pattern, e.g., to over-express.Thus, the term “exogenous” gene or DNA is intended to refer to any geneor DNA segment that is introduced into a recipient cell, regardless ofwhether a similar gene may already be present in such a cell. The typeof DNA included in the exogenous DNA can include DNA which is alreadypresent in the plant cell, DNA from another plant, DNA from a differentorganism, or a DNA generated externally, such as a DNA sequencecontaining an antisense message of a gene, or a DNA sequence encoding asynthetic or modified version of a gene.

Many hundreds if not thousands of different genes are known and couldpotentially be introduced into a plant of lettuce variety 41-122 RZ.Non-limiting examples of particular genes and corresponding phenotypesone may choose to introduce into a lettuce plant include one or moregenes for insect tolerance, pest tolerance such as genes for fungaldisease control, herbicide tolerance, and genes for quality improvementssuch as yield, nutritional enhancements, environmental or stresstolerances, or any desirable changes in plant physiology, growth,development, morphology or plant product(s).

Alternatively, the DNA coding sequences can affect these phenotypes byencoding a non-translatable RNA molecule that causes the targetedinhibition of expression of an endogenous gene, for example viaantisense- or cosuppression-mediated mechanisms. The RNA could also be acatalytic RNA molecule (i.e., a ribozyme) engineered to cleave a desiredendogenous mRNA product. Thus, any gene which produces a protein or mRNAwhich expresses a phenotype or morphology change of interest is usefulfor the practice of the present invention. (See also U.S. Pat. No.7,576,262, “Modified gene-silencing RNA and uses thereof.”)

U.S. Pat. Nos. 7,230,158, 7,122,720, 7,081,363, 6,734,341, 6,503,732,6,392,121, 6,087,560, 5,981,181, 5,977,060, 5,608,146, 5,516,667, eachof which, and all documents cited therein are hereby incorporated hereinby reference, consistent with the above INCORPORATION BY REFERENCEsection, are additionally cited as examples of U.S. patents that mayconcern transformed lettuce and/or methods of transforming lettuce orlettuce plant cells, and techniques from these US patents, as well aspromoters, vectors, etc., may be employed in the practice of thisinvention to introduce exogenous nucleic acid sequence(s) into a plantof lettuce variety 41-122 RZ (or cells thereof), and exemplify someexogenous nucleic acid sequence(s) which can be introduced into a plantof lettuce variety 41-122 RZ (or cells thereof) of the invention, aswell as techniques, promoters, vectors etc., to thereby obtain furtherplants of lettuce variety 41-122 RZ, plant parts and cells, seeds, otherpropagation material harvestable parts of these plants, etc. of theinvention, e.g. tissue culture, including a cell or protoplast, such asan embryo, meristem, cotyledon, pollen, leaf, anther, root, root tip,pistil, flower, seed or stalk.

The invention further relates to propagation material for producingplants of the invention. Such propagation material comprises inter aliaseeds of the claimed plant and parts of the plant that are involved insexual reproduction. Such parts are for example selected from the groupconsisting of seeds, microspores, pollen, ovaries, ovules, embryo sacsand egg cells. In addition, the invention relates to propagationmaterial comprising parts of the plant that are suitable for vegetativereproduction, for example cuttings, roots, stems, cells, protoplasts.

According to a further aspect thereof the propagation material of theinvention comprises a tissue culture of the claimed plant. The tissueculture comprises regenerable cells. Such tissue culture can be derivedfrom leaves, pollen, embryos, cotyledon, hypocotyls, meristematic cells,roots, root tips, anthers, flowers, seeds and stems. (See generally U.S.Pat. No. 7,041,876 on lettuce being recognized as a plant that can beregenerated from cultured cells or tissue).

Also, the invention comprehends methods for producing a seed of a“41-122 RZ”-derived lettuce plant comprising (a) crossing a plant oflettuce variety 41-122 RZ, representative seed of which having beendeposited under NCIMB Accession No. NCIMB 41832, with a second lettuceplant, and (b) whereby seed of a “41-122 RZ”-derived lettuce plant form(e.g., by allowing the plant from the cross to grow to producing seed).Such a method can further comprise (c) crossing a plant grown from“41-122 RZ”-derived lettuce seed with itself or with a second lettuceplant to yield additional “41-122 RZ”-derived lettuce seed, (d) growingthe additional “41-122 RZ”-derived lettuce seed of step (c) to yieldadditional “41-122 RZ”-derived lettuce plants, and (e) repeating thecrossing and growing of steps (c) and (d) to generate further “41-122RZ”-derived lettuce plants.

The invention additionally provides a method of introducing a desiredtrait into a plant of lettuce variety 41-122 RZ comprising: (a) crossinga plant of lettuce variety 41-122 RZ, representative seed of whichhaving been deposited under NCIMB Accession No. NCIMB 41832, with asecond lettuce plant that comprises a desired trait to produce F1progeny; (b) selecting an F1 progeny that comprises the desired trait;(c) crossing the selected F1 progeny with a plant of lettuce variety41-122 RZ, to produce backcross progeny; (d) selecting backcross progenycomprising the desired trait and the physiological and morphologicalcharacteristic of a plant of lettuce variety 41-122 RZ; and, optionally,(e) repeating steps (c) and (d) one or more times in succession toproduce selected fourth or higher backcross progeny that comprise thedesired trait and all of the physiological and morphologicalcharacteristics of a plant of lettuce variety 41-122 RZ, when grown inthe same environmental conditions. The invention, of course, includes alettuce plant produced by this method.

Backcrossing can also be used to improve an inbred plant. Backcrossingtransfers a specific desirable trait from one inbred or non-inbredsource to an inbred that lacks that trait. This can be accomplished, forexample, by first crossing a superior inbred (A) (recurrent parent) to adonor inbred (non-recurrent parent), which carries the appropriate locusor loci for the trait in question. The progeny of this cross are thenmated back to the superior recurrent parent (A) followed by selection inthe resultant progeny for the desired trait to be transferred from thenon-recurrent parent. After five or more backcross generations withselection for the desired trait, the progeny are heterozygous for locicontrolling the characteristic being transferred, but are like thesuperior parent for most or almost all other loci. The last backcrossgeneration would be selfed to give pure breeding progeny for the traitbeing transferred. When a plant of lettuce variety 41-122 RZ,representative seed of which having been deposited under NCIMB AccessionNo. NCIMB 41832, is used in backcrossing, offspring retaining thecombination of traits including resistance against downy mildew (Bremialactucae), leaves with a solid main vein, narrow base leaves, and thick,strongly blistered, mature leaves are progeny within the ambit of theinvention. Backcrossing methods can be used with the present inventionto improve or introduce a characteristic into a plant of the invention,being a plant of lettuce variety 41-122 RZ. See, e.g., U.S. Pat. No.7,705,206 (incorporated herein by reference consistent with the aboveINCORPORATION BY REFERENCE section), for a general discussion relatingto backcrossing.

The invention further involves a method of determining the genotype of aplant of lettuce variety 41-122 RZ, representative seed of which hasbeen deposited under NCIMB Accession No. NCIMB 41832, or a firstgeneration progeny thereof, comprising obtaining a sample of nucleicacids from said plant and detecting in said nucleic acids a plurality ofpolymorphisms. This method can additionally comprise the step of storingthe results of detecting the plurality of polymorphisms on a computerreadable medium. The plurality of polymorphisms are indicative of and/orgive rise to the expression of the morphological and physiologicalcharacteristics of lettuce variety 41-122 RZ.

Lettuce leaves are sold in packaged form, including without limitationas pre-packaged lettuce salad or as lettuce heads. Mention is made ofU.S. Pat. No. 5,523,136, incorporated herein by reference consistentwith the above INCORPORATION BY REFERENCE section, which providespackaging film, and packages from such packaging film, including suchpackaging containing leafy produce, and methods for making and usingsuch packaging film and packages, which are suitable for use with thelettuce leaves of the invention. Thus, the invention comprehends the useof and methods for making and using the leaves of the lettuce plant ofthe invention, as well as leaves of lettuce plants derived from theinvention. The invention further relates to a container comprising oneor more plants of the invention, or one or more lettuce plants derivedfrom a plant of the invention, in a growth substrate for harvest ofleaves from the plant in a domestic environment. This way the consumercan pick very fresh leaves for use in salads. More generally, theinvention includes one or more plants of the invention or one or moreplants derived from lettuce of the invention, wherein the plant is in aready-to-harvest condition, including with the consumer picking his own,and further including a container comprising one or more of theseplants.

The invention is further described by the following numbered paragraphs:

1. Lettuce plant exhibiting a combination of traits including resistanceagainst downy mildew (Bremia lactucae Regel), leaves with a solid mainvein, narrow base leaves, and thick, strongly blistered, dark greenmature leaves, representative seed of which having been deposited underNCIMB Accession No. 41832.

2. Lettuce plant exhibiting a combination of traits including resistanceagainst downy mildew (Bremia lactucae Regel), leaves with a solid mainvein, narrow base leaves, thick, strongly blistered, dark green matureleaves, a short core, absence of fringe burn, absence of tipburn, noundulation of the fourth leaf, and very slow bolting, representativeseed of which having been deposited under NCIMB Accession No. 41832.

3. Lettuce plant designated 41-122 RZ, representative seed of whichhaving been deposited under NCIMB Accession No. 41832.

4. A seed of the plant of paragraph 1.

5. Parts of the plant of paragraph 1, wherein said parts of the plantare suitable for sexual reproduction.

6. Parts of the plant of paragraph 5, said parts selected from the groupconsisting of microspores, pollen, ovaries, ovules, embryo sacs and eggcells.

7. Parts of the plant of paragraph 1, wherein said parts of the plantare suitable for vegetative reproduction.

8. Parts of paragraph 7, said parts selected from the group consistingof cuttings, roots, stems, cells and protoplasts.

9. A tissue culture of regenerable cells from the lettuce plant ofparagraph 1.

10. A tissue culture of paragraph 9, wherein said cells or protoplastsof the tissue culture which are derived from a tissue selected from thegroup consisting of leaves, pollen, embryos, cotyledon, hypocotyls,meristematic cells, roots, root tips, anthers, flowers, seeds and stems.

11. Progeny of a lettuce plant of paragraph 1.

12. Progeny of paragraph 11, wherein said progeny is produced by sexualor vegetative reproduction of said lettuce plant, and wherein saidprogeny exhibits a combination of traits including resistance againstdowny mildew (Bremia lactucae), leaves with a solid main vein, narrowbase leaves, and thick, strongly blistered, dark green mature leaves.

13. Progeny of a lettuce plant of paragraph 3, having all themorphological and physiological characteristics of the lettuce plant ofparagraph 3, representative seed of which having been deposited underNCIMB Accession No. 41832 wherein as found in lettuce variety 41-122 RZ,representative seed of which having been deposited under NCIMB AccessionNo. 41832.

14. Progeny of a lettuce plant of paragraph 1, representative seed ofwhich having been deposited under NCIMB Accession 41832, and is modifiedin one or more other characteristics.

15. Progeny of paragraph 14, wherein the modification is effected bymutagenesis.

16. Progeny of paragraph 14, wherein the modification is effected bytransformation with a transgene.

17. A method of producing a hybrid lettuce seed comprising crossing afirst parent lettuce plant with a second parent lettuce plant andharvesting the resultant hybrid lettuce seed, wherein said first parentlettuce plant or said second parent lettuce plant is the lettuce plantof paragraph 1.

18. A method of producing a lettuce cultivar containing a combination oftraits including resistance against downy mildew (Bremia lactucae),leaves with a solid main vein, narrow base leaves, and thick, stronglyblistered, dark green mature leaves, comprising: crossing a motherlettuce plant with a father lettuce plant to produce a hybrid seed;growing said hybrid seed to produce a hybrid plant; selfing said hybridseed to produce F2 progeny seed; selecting said F2-plants for exhibitingresistance against downy mildew (Bremia lactucae), leaves with a solidmain vein, narrow base leaves, and thick, strongly blistered, dark greenmature leaves, and, selfing said selected F2-plants to produce F3progeny seed; selecting F3-plants for exhibiting resistance againstdowny mildew (Bremia lactucae), leaves with a solid main vein, narrowbase leaves, and thick, strongly blistered, dark green mature leaves,optionally followed by more selfing and selection steps.

19. A method for producing lettuce leaves as a fresh vegetablecomprising packaging leaves of a plant of paragraph 1.

20. A method for producing lettuce leaves as a processed food comprisingprocessing leaves of a plant of paragraph 1.

21. One or more lettuce plants of paragraph 1, in a container, forharvest of leaves.

22. Lettuce plant having morphological and/or physiologicalcharacteristics of a lettuce plant, representative seed of which havingbeen deposited under NCIMB Accession No. 41832.

23. Lettuce plant of paragraph 22 having all the morphological andphysiological characteristics of the lettuce plant, representative seedof which having been deposited under NCIMB Accession No. 41832.

24. A method of introducing a desired trait into a plant of lettucevariety 41-122 RZ comprising: (a) crossing a plant of lettuce variety41-122 RZ, representative seed of which having been deposited underNCIMB Accession No. NCIMB 41832, with a second lettuce plant thatcomprises the desired trait to produce F1 progeny; (b) selecting an F1progeny that comprises the desired trait; (c) crossing the selected F1progeny with a plant of lettuce variety 41-122 RZ, to produce backcrossprogeny and (d) selecting backcross progeny comprising the desired traitand the physiological and morphological characteristic of a plant oflettuce variety 41-122 RZ, when grown in the same environmentalconditions.

25. The method of paragraph 24 further comprising (e) repeating steps(c) and (d) one or more times in succession to produce selected fourthor higher backcross progeny that comprise the desired trait and all ofthe physiological and morphological characteristics of a plant oflettuce variety 41-122 RZ, when grown in the same environmentalconditions.

26. A lettuce plant produced by the method of paragraph 24 or 25.

27. A method for producing a seed of a 41-122 RZ-derived lettuce plantcomprising (a) crossing a plant of lettuce variety 41-122 RZ,representative seed of which having been deposited under NCIMB AccessionNo. NCIMB 41832, with a second lettuce plant, and (b) whereby seed of a41-122 RZ-derived lettuce plant form.

28. The method of paragraph 27 further comprising (c) crossing a plantgrown from 41-122 RZ-derived lettuce seed with itself or with a secondlettuce plant to yield additional 41-122 RZ-derived lettuce seed, (d)growing the additional 41-122 RZ-derived lettuce seed of step (c) toyield additional 41-122 RZ-derived lettuce plants, and (e) repeating thecrossing and growing of steps (c) and (d) to generate further 41-122RZ-derived lettuce plants.

29. A method of determining the genotype of a plant of lettuce variety41-122 RZ, representative seed of which has been deposited under NCIMBAccession No. NCIMB 41832, or a first generation progeny thereof,comprising obtaining a sample of nucleic acids from said plant anddetecting in said nucleic acids a plurality of polymorphisms, whereinthe plurality of polymorphisms are indicative of and/or give rise to theexpression of the morphological and physiological characteristics oflettuce variety 41-122 RZ.

30. The method of paragraph 29 additionally comprising the step ofstoring the results of detecting the plurality of polymorphisms on acomputer readable medium, or transmitting the results of detecting theplurality of polymorphisms.

Having thus described in detail preferred embodiments of the presentinvention, it is to be understood that the invention is not to belimited to particular details set forth in the above description as manyapparent variations thereof are possible without departing from thespirit or scope of the present invention.

What is claimed is:
 1. A lettuce plant exhibiting a combination oftraits including resistance against downy mildew (Bremia lactucaeRegel), leaves with a solid main vein, narrow base leaves, and thick,strongly blistered, dark green mature leaves, representative seed ofwhich having been deposited under NCIMB Accession No.
 41832. 2. Thelettuce plant of claim 1 further exhibiting a combination of traitsincluding a short core, absence of fringe burn, absence of tipburn, noundulation of the fourth leaf, and very slow bolting.
 3. A seed of theplant of claim
 1. 4. Parts of the plant of claim 1, wherein said partsof the plant are suitable for sexual reproduction or wherein said partsof the plant are suitable for sexual reproduction and wherein said partsare selected from the group consisting of microspores, pollen, ovaries,ovules, embryo sacs and egg cells or wherein said parts of the plant aresuitable for vegetative reproduction or wherein said parts of the plantare suitable for vegetative reproduction and wherein said parts selectedfrom the group consisting of cuttings, roots, stems, cells andprotoplasts.
 5. A tissue culture of regenerable cells from the lettuceplant of claim 1, optionally wherein said cells or protoplasts of thetissue culture are derived from a tissue selected from the groupconsisting of leaves, pollen, embryos, cotyledon, hypocotyls,meristematic cells, roots, root tips, anthers, flowers, seeds and stems.6. Progeny of a lettuce plant of claim 1, wherein said progeny exhibitsa combination of traits including resistance against downy mildew(Bremia lactucae), leaves with a solid main vein, narrow base leaves,and thick, strongly blistered, dark green mature leaves.
 7. Progeny asclaimed in claim 6, wherein said progeny is produced by sexual orvegetative reproduction of said lettuce plant.
 8. Progeny of a lettuceplant of claim 1, representative seed of which having been depositedunder NCIMB Accession 41832, wherein the progeny exhibits thecombination of traits of the lettuce plant of claim 1, and is furthermodified in one or more other characteristics.
 9. Progeny as claimed inclaim 8, wherein the modification is effected by mutagenesis or whereinthe modification is effected by transformation with a transgene.
 10. Amethod of producing a hybrid lettuce seed comprising crossing a firstparent lettuce plant with a second parent lettuce plant and harvestingthe resultant hybrid lettuce seed, wherein said first parent lettuceplant or said second parent lettuce plant is the lettuce plant of claim1 or a method of producing a lettuce cultivar containing a combinationof traits including resistance against downy mildew (Bremia lactucae),leaves with a solid main vein, narrow base leaves, and thick, stronglyblistered, dark green mature leaves, comprising: crossing a motherlettuce plant with a father lettuce plant to produce a hybrid seed;growing said hybrid seed to produce a hybrid plant; selfing said hybridseed to produce F2 progeny seed; selecting said F2-plants for exhibitingresistance against downy mildew (Bremia lactucae), leaves with a solidmain vein, narrow base leaves, and thick, strongly blistered, dark greenmature leaves, and, selfing said selected F2-plants to produce F3progeny seed; selecting F3-plants for exhibiting resistance againstdowny mildew (Bremia lactucae), leaves with a solid main vein, narrowbase leaves, and thick, strongly blistered, dark green mature leaves,optionally followed by more selfing and selection steps.
 11. A methodfor producing lettuce leaves as a fresh vegetable comprising packagingleaves of a plant of claim
 1. 12. A method for producing lettuce leavesas a processed food comprising processing leaves of a plant of claim 1.13. A lettuce plant having morphological and/or physiologicalcharacteristics of a lettuce plant, representative seed of which havingbeen deposited under NCIMB Accession No. 41832, and wherein said lettuceplant exhibits a combination of traits including resistance to downymildew (Bremia Lactucae Regel), leaves with a solid main vein, narrowbase leaves, and thick strongly blistered, dark green mature leaves. 14.The lettuce plant of claim 13 having all the morphological andphysiological characteristics of the lettuce plant, representative seedof which having been deposited under NCIMB Accession No.
 41832. 15. Amethod of introducing a desired trait into a plant of lettuce variety41-122 RZ comprising: (a) crossing a plant of lettuce variety 41-122 RZ,representative seed of which having been deposited under NCIMB AccessionNo. NCIMB 41832, with a second lettuce plant that comprises the desiredtrait to produce F1 progeny; (b) selecting an F1 progeny that comprisesthe desired trait; (c) crossing the selected F1 progeny with a plant oflettuce variety 41-122 RZ, to produce backcross progeny and (d)selecting backcross progeny comprising the desired trait and all of thephysiological and morphological characteristics of a plant of lettucevariety 41-122 RZ, when grown in the same environmental conditions. 16.The method of claim 15 further comprising (e) repeating steps (c) and(d) one or more times in succession to produce selected fourth or higherbackcross progeny that comprise the desired trait and all of thephysiological and morphological characteristics of a plant of lettucevariety 41-122 RZ, when grown in the same environmental conditions. 17.A lettuce plant produced by the method of claim
 15. 18. A method forproducing a seed of a 41-122 RZ-derived lettuce plant comprising (a)crossing a plant of lettuce variety 41-122 RZ, representative seed ofwhich having been deposited under NCIMB Accession No. NCIMB 41832, witha second lettuce plant, and (b) whereby seed of a 41-122 RZ-derivedlettuce plant form.
 19. The method of claim 18 further comprising (c)crossing a plant grown from 41-122 RZ-derived lettuce seed with itselfor with a second lettuce plant to yield additional 41-122 RZ-derivedlettuce seed, (d) growing the additional 41-122 RZ-derived lettuce seedof step (c) to yield additional 41-122 RZ-derived lettuce plants, and(e) repeating the crossing and growing of steps (c) and (d) to generatefurther 41-122 RZ-derived lettuce plants.
 20. A method of determiningthe genotype of a plant of lettuce variety 41-122 RZ, representativeseed of which has been deposited under NCIMB Accession No. NCIMB 41832,or a first generation progeny thereof, comprising obtaining a sample ofnucleic acids from said plant and detecting in said nucleic acids aplurality of polymorphisms, wherein the plurality of polymorphisms areindicative of and/or give rise to the expression of the morphologicaland physiological characteristics of lettuce variety 41-122 RZ andoptionally additionally comprising the step of storing the results ofdetecting the plurality of polymorphisms on a computer readable medium,or transmitting the results of detecting the plurality of polymorphisms.21. A lettuce plant designated 41-122 RZ, representative seed of whichhaving been deposited under NCIMB Accession No.
 41832. 22. Progeny of alettuce plant designated 41-122 RZ, representative seed of which havingbeen deposited under NCIMB Accession No. 41832, having all themorphological and physiological characteristics of the lettuce plantdesignated 41-122 RZ.
 23. A lettuce plant exhibiting a combination oftraits including resistance against downy mildew (Bremia lactucaeRegel), leaves with a solid main vein, narrow base leaves, and thick,strongly blistered, dark green mature leaves and having genetic materialfor so exhibiting the combination of traits; wherein the geneticinformation is as contained in a plant, representative seed of whichhaving been deposited under NCIMB Accession No. 41832.